Developmental plasticity in reptiles: Insights from temperature-dependent gene expression in wall lizard embryos

Area of Science:

• Developmental Biology
• Ecology and Evolutionary Biology
• Genomics

Background:

• Incubation temperature is a critical factor influencing reptile development.
• However, its specific effects on gene expression remain largely uncharacterized.
• Understanding these effects is crucial for predicting reptile responses to climate change.

Purpose of the Study:

• To investigate the impact of incubation temperature on gene expression profiles in common wall lizard (Podarcis muralis) embryos.
• To identify specific genes and pathways affected by thermal stress during early development.
• To explore potential epigenetic mechanisms involved in thermal acclimation.

Main Methods:

• Utilized a split-clutch design with common wall lizards from four populations.
• Incubated embryos at two distinct temperatures: stressfully low (15°C) and benign (24°C).
• Analyzed gene expression profiles at a precisely defined developmental stage (by somite number) using transcriptomic analysis.

Main Results:

• Embryos at 15°C showed approximately 20% less total RNA compared to those at 24°C, indicating reduced transcription rates.
• After normalization, about 50% of all transcripts exhibited significant expression differences between temperature groups.
• Key affected transcripts were associated with transcriptional/translational regulation and chromatin remodeling.

Conclusions:

• Incubation temperature profoundly alters gene expression in early wall lizard embryos.
• Changes in gene expression suggest epigenetic modifications may facilitate acclimation to cool temperatures.
• Findings highlight the utility of transcriptomics in understanding reptile adaptation to thermal stress.